IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
Revealing the pulsational properties of the V777 Her star KUV 05134+2605 by its long-term monitoring
Autor/es:
Z. BOGNÁR; M. PAPARÓ; A. H. CÓRSICO; S. O. KEPLER; A. GYőRFFY
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2014 vol. 570 p. 116 - 131
ISSN:
0004-6361
Resumen:
Context. KUV 05134+2605 is one of the 21 pulsating DB
white dwarfs (V777 Her or DBV variables) known so far. The detailed
investigation of the short-period and low-amplitude pulsations of these
relatively faint targets requires considerable observational efforts
from the ground, long-term single-site or multi-site observations. The
observed amplitudes of excited modes undergo short-term variations in
many cases, which makes determining pulsation modes difficult.
Aims: We aim to determine the pulsation frequencies of KUV 05134+2605,
find regularities between the frequency and period components, and
perform an asteroseismic investigation for the first time.
Methods: We re-analysed the published data and collected new
measurements. We compared the frequency content of the different
datasets from the different epochs and performed various tests to check
the reliability of the frequency determinations. The mean period
spacings were investigated with linear fits to the observed periods,
Kolmogorov-Smirnov and inverse variance significance tests, and with a
Fourier analysis of different period sets, including a Monte Carlo test
that simulated the effect of alias ambiguities. We employed fully
evolutionary DB white dwarf models for the asteroseismic investigations.
Results: We identified 22 frequencies between 1280 and 2530
μHz. These form 12 groups, which suggests at least 12 possible
frequencies for the asteroseismic investigations. Thanks to the extended
observations, KUV 05134+2605 joined the group of rich white dwarf
pulsators. We identified one triplet and at least one doublet with a
≈ 9 μHz frequency separation, from which we derived a stellar
rotation period of 0.6 d. We determined the mean period spacings of ≈
31 s and 18 s for the modes we propose as dipole and quadrupole. We
found an excellent agreement between the stellar mass derived from the
ℓ = 1 period spacing and the period-to-period fits, all providing
M∗ = 0.84 - 0.85 M⊙ solutions. Our
study suggests that KUV 05134+2605 is the most massive amongst the known
V777 Her stars.